This invention relates to polymeric enzyme products. More specifically, it relates to novel immobilied microbial cells and their preparation.
Enzymes, with their high degree of specificity, are far superior to conventional catalysts in many chemical reactions. Until recently, however, such factors as the high cost of isolation, the tendency toward instability when removed from the environment of the whole cell, and the availability only in soluble form, had severely limited enzyme use.
The immobilization of enzymes by attachment to, or entrapment within, solid support material has helped to overcome some of these difficulties and to make enzyme use more economical. The various physical and chemical methods employed for the immobilization are discussed in such reviews as Immobilized Enzymes by O. R. Zaborsky (CRC Press, 1973).
Immobilization of the whole cell itself to overcome enzyme isolation and stability problems has also been employed. Its use to date, however, has been limited to physical methods of immobilization. Typical examples are the adsorption of cells of Streptomyces phaeochromogenes containing active glucose isomerase on reconstituted hide collagen (Biotech. & Bioengr., XV, p. 565 (1973), and the gel entrapment of fungal cells containing hydroxylase enzyme for the conversion of Compound S to cortisol (Scientific American, Mar. 1971, p. 30). These immobilization methods do not, however, preclude disassociation of the cells from the support medium. The nature of the binding forces is such that reaction conditions may be severely limited in order to prevent or minimize such disassociation with attendant loss of enzymatic activity and possible contamination of the process stream. A more stable cell immobilization system is therefore the object of this invention.